package com.ylkj.common.security.des;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.security.SecureRandom;

/**
 * DES对称加密解密工具类
 * 
 * @author zhaoshijie
 * 
 */
public class DesSecurityUtil implements Security {
	private final static String DES = "DES";

	/**
	 * 功能描述: 加密
	 * @param src
	 * @param key
	 * @return
	 * @throws Exception
	 */
	private byte[] encrypt(byte[] src, byte[] key) throws Exception {
		// DES算法要求有一个可信任的随机数源
		SecureRandom sr = new SecureRandom();
		// 从原始密匙数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);
		// 创建一个密匙工厂，然后用它把DESKeySpec转换成
		// 一个SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);
		// Cipher对象实际完成加密操作
		Cipher cipher = Cipher.getInstance(DES);
		// 用密匙初始化Cipher对象
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
		// 现在，获取数据并加密
		// 正式执行加密操作
		return cipher.doFinal(src);
	}

	/**
	 * 功能描述: 解密
	 * @param src
	 * @param key
	 * @return
	 * @throws Exception
	 */
	private byte[] decrypt(byte[] src, byte[] key) throws Exception {
		// DES算法要求有一个可信任的随机数源
		SecureRandom sr = new SecureRandom();
		// 从原始密匙数据创建一个DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);
		// 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
		// 一个SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);
		// Cipher对象实际完成解密操作
		Cipher cipher = Cipher.getInstance(DES);
		// 用密匙初始化Cipher对象
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
		// 现在，获取数据并解密
		// 正式执行解密操作
		return cipher.doFinal(src);
	}
	
	
	/**
	 * 功能描述: 二行制转字符串
	 * @param b
	 * @return
	 */
	private String byte2hex(byte[] b) {
		String hs = "";
		String stmp = "";
		for (int n = 0; n < b.length; n++) {
			stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
			if (stmp.length() == 1)
				hs = hs + "0" + stmp;
			else
				hs = hs + stmp;
		}
		return hs.toUpperCase();
	}

	private byte[] hex2byte(byte[] b) {
		if ((b.length % 2) != 0)
			throw new IllegalArgumentException("长度不是偶数");
		byte[] b2 = new byte[b.length / 2];
		for (int n = 0; n < b.length; n += 2) {
			String item = new String(b, n, 2);
			b2[n / 2] = (byte) Integer.parseInt(item, 16);
		}
		return b2;
	}


	/* 
	 * 解密
	 * (non-Javadoc)
	 * @see utils.security.des.Encrypt#decryptData(java.lang.String, java.lang.String)
	 */
	public String decryptData(String key, String data) {
		try {
			return new String(
					decrypt(hex2byte(data.getBytes()), key.getBytes()));
		} catch (Exception e) {
		}
		return data;
	}

	/* 
	 * 加密
	 * (non-Javadoc)
	 * @see utils.security.des.Encrypt#encryptData(java.lang.String, java.lang.String)
	 */
	public String encryptData(String key, String data) {
		try {
			return byte2hex(encrypt(data.getBytes(), key.getBytes()));
		} catch (Exception e) {
		}
		return data;
	}
	
	public static void main(String[] args) {
		DesSecurityUtil u = new DesSecurityUtil();
		//加密
		String abc = u.encryptData("9xZ83wuKDVdYrtWn+xz0O8ebNBBKuVhb", "13311140920");
		System.out.println(abc);
		
		//解密
		System.out.println(u.decryptData("9xZ83wuKDVdYrtWn+xz0O8ebNBBKuVhb", abc));
		
	}
}
